Question

9) Write out the following method as a static method for the IntNode class (similar to the book: use data & link) public static int count10s (IntNode head) I Precondition: Head is a reference to a linked list of integers, Il condition of the list is unknown (empty or not) // Postcondition: Method returns number of 10s found in the linked list. / list is unchanged. 10) Write out the following method as a static method for the IntNode class (similar to the book: use data & link) public static void insertAtTail IntNode head, int value) // Precondition: Head is a reference to a linked list of integers, condition of the list is unknown (empty or not), int refers to value to be // added to the list at the END Postcondition List will have an additional node with the value placed in it Note] break this into two parts -finding the right spot and then inserting. The insert you already described up above you just need to look for the last node; that node's link can be looked at as the "head" to your new node. Don't forget to watch for empty case.

Answer 1

$\color{blue}\underline{IntNode.java:}$

class IntNode {
    int value;
    IntNode next;

    public IntNode(int value) {
        this.value = value;
        this.next = null;
    }
}

$\color{blue}\underline{IntNodeMain.java:}$

public class IntNodeMain {

    public static int count10s(IntNode head) {
        IntNode temp = head;
        int count = 0;
        while (temp != null) {
            if(temp.value == 10) {
                count++;
            }
            temp = temp.next;
        }
        return count;
    }

    public static void insertAtTail(IntNode head, int value) {
        IntNode n = new IntNode(value);
        if(head == null) {
            head = n;
        }
        IntNode temp = head;
        while (temp.next != null) {
            temp = temp.next;
        }
        temp.next = n;
    }

    public static void main(String[] args) {
        IntNode head = new IntNode(10);
        insertAtTail(head, 6);
        insertAtTail(head, 3);
        insertAtTail(head, 10);
        insertAtTail(head, 4);
        System.out.println("Number of 10s: " + count10s(head));
    }

}